JT-60U MONTHLY SUMMARY

April 1997

OPERATION AND CONFINEMENT PHYSICS

In the 4th ITER expert meetings on "Confinement and Transport"
and "Confinement Database and Modeling", the JT-60 Team reported
the results of the power threshold for the H-mode transition, demonstration
of ITER-like discharges, ELM behavior and the advanced tokamak scenario
including reversed magnetic shear. In particular, effects of wall condition
and behavior of neutrals on confinement characteristics were emphasized.

CURRENT DRIVE AND HIGH ENERGY PARTICLE PHYSICS

Following topics were presented as an invited paper in the 12th Topical
Conference on Radio Frequency Power in Plasmas, Savannah, April 1-3; 1)
Sustainment of a negative magnetic shear configuration for up to 7.5 s,
2) Control of the location of qmin in a negative magnetic shear configuration
by LHCD, 3) Combined current drive with LHCD and N-NBCD (350 keV), 4) ICRF
heating of negative shear plasmas by changing ICRF/NBI power ratio, 5) Multiple
TAE modes inside q=1 surface and 6) Dependence of Antenna voltage limit
on plasma shape.

DIVERTOR AND BOUNDARY PHYSICS

The construction of the W-shaped divertor for JT-60U was favorably in progress.
Divertor plates, baffle supports and plates and domes were fabricated, and
most of CFC tiles and graphite tiles were set on these plates by the end
of April. The installation of new divertor diagnostics was completed. The
divertor operation working group discussed functional tests and operation
scenarios for the new divertor system in the first experimental period in
June.